The present invention relates to a control apparatus for a vehicle in which a central control unit is synergically or systematically connected to respective control means through data transmission lines so as to improve the total reliability and performance of the vehicle.
A known typical electronic control apparatus for a vehicle, for example, controls respective control means such as an engine, a transmission, a brake system, a suspension system, etc., independently of each other, and to this end, it generally has separate sensors required to control each of the control means and controls, based on the outputs of corresponding sensors, an actuator for each control means. In contrast, a new idea of commonly utilizing data for varying electronic control devices through data communications therebetween has recently been developed. For example, such an idea is described in SAE Technical Paper Series No. 860390 by Frederick H. Phall and David J. Arnett, entitled "In-Vehicle Networking-Serial Communication Requirements and Directions", or an Article Reprint No. AR-507 by Ronald K. Jurgen of IEEE Spectrum issued in September 1986, entitled "Coming from Detroit: Network on Wheels", or an article by David J. Arnett, entitled "IEEE WORKSHOP ON AUTOMOTIVE APPLICATIONS OF ELECTRONICS".
FIG. 2 shows the general arrangement of an example of a known control apparatus for a vehicle. The known apparatus illustrated includes a switch means comprising various switches operated by the driver of a vehicle, an instrument panel 2 having various meters, indicators and the like for indicating the travelling conditions of the vehicle, an engine control means 3 equipped with various sensors 13, a transmission control means 4 with sensors 14, a suspension control means 5 with sensors 15, a brake control means 6 with sensors 16, a traction control means 7 with sensors 17, an air conditioner control means 8, a navigator 9, a trip computer 10, various lamps 18, a mirror/window drive motor 19, audio/visual equipment 20, a seat motor 21, a wiper motor 22, a diagnosis device 23, a real time bus 24 for transmitting control signals to actuators 28, an information bus 25 for transmitting information, a body control bus 26 for transmitting signals to the switches and the motors so as to control the body of the vehicle, a gateway 27 connecting between the buses 24, 25 and 26, a first processor 11 for converting signals between the buses 24, 25, and a second processor 12 for converting signals between the buses 25, 26.
The above-described known control apparatus as constructed above operates as follows. First, the respective control means 3 through 7 receive signals from the corresponding sensors 13 through 17, perform necessary calculations based thereon, and drive and control the corresponding actuators 28 through the real time bus 24 in accordance with the result of the calculations. On the other hand, the signals from the various sensors 13 through 17 are also fed to the information bus 25. Thus, signals from the switch means 1, which are manipulated by the driver, are fed to the air conditioner control means 8, the navigator 9 and the trip computer 10 which in turn drive and control, based thereon, the corresponding actuators 28, and which at the same time send signals indicative of their operating conditions to the information bus 25. The lamps 18, the mirror/window drive motor 19, the audio/visual equipment 20, the seat motor 21 and the wiper motor 22 are directly driven by the signals from the driver-operated switch means 1. The signals on the information bus 25 are input to the meters and indicators on the instrument panel 2 so as to display information necessary to the driver.
Further, the signals on the information bus 25 are also input to the diagnosis device 23 which diagnoses, based thereon, the functionalities such as faults of the sensors 13 through 17. The real time bus 24 and the information bus 25 are interconnected to each other through the gateway 27 with the first processor 11 interposed therein so as to supply the signals on the real time bus 24 to the diagnosis device 23. Similarly, the body control bus 26 and the information bus 25 are interconnected to each other through the gateway 27 with the second processor 12 interposed therein so as to supply the signals on the body control bus 26 to the diagnosis device 23 and the meters and indicators on the instrument panel 2.
With the above-mentioned known control apparatus for a vehicle, the respective control means 3 through 7 perform the respective control operations independently of each other, so that only the signal lines for driving the actuators 28 and the signals from the driver-operated switches 1 are merely multiplexed or commonly used. Further, the sensors 13 through 17 merely generate signals for the purpose of displaying information on the instrument panel 2. Accordingly, it is neither economical nor logical to install communication ICs on the respective control means 3 through 7 for communication therebetween without providing any additional functions. Moreover, the real time bus 24 for driving the actuators 28 is of very much significance and if there takes place a malfunction or fault in the bus 24, the entire system is forced to cease its intended functions, making any further continued travel of the vehicle impossible.